CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT

Why there is an Oblique shock inside the Cd nozzle for the ideal flow condition?

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 14, 2020, 04:39
Default Why there is an Oblique shock inside the Cd nozzle for the ideal flow condition?
  #1
New Member
 
Nirmal
Join Date: May 2020
Posts: 2
Rep Power: 0
snirmal30 is on a distinguished road
Using the Area ratio (A/A*) and for the desired exit Mach number I have designed a cd nozzle. The Inlet total pressure (Po) and the total temperature (To) is calculated using Isentropic relations for the optimum condition.

Nozzle divergence angle: 6 degree

Mesh Orthogonal Quality:
Nodes: 51660
Min: 0.9724
Max: 1
Average: 0.997

CONDITIONS:
Solver type: Density-based, Absolute, 2d, Axisymmetric

Model: Energy On, Inviscid

Material: Air (Ideal gas)

Boundary condition:
Inlet- Pressure inlet- 792812.3356 Pa; Supersonic/Initial Gauge pressure: 700000 Pa; Total Temperature: 518.4 K
Outlet- Pressure outlet- 101325 Pa; Backflow total temperature: 288 K
Operating condition- 0 Pa
Wall- Wall

For this condition, I should get an ideal flow throughout the nozzle, but there's an oblique shock inside the cd nozzle. Is this a design flaw or any error in the conditions?
Attached Images
File Type: jpg mach contour.JPG (74.5 KB, 9 views)
File Type: jpg velocity contour.JPG (77.1 KB, 8 views)
File Type: jpg geometry.JPG (29.7 KB, 5 views)
snirmal30 is offline   Reply With Quote

Old   May 14, 2020, 07:20
Default Shock
  #2
Senior Member
 
vinerm's Avatar
 
Vinerm
Join Date: Jun 2009
Location: Nederland
Posts: 2,946
Blog Entries: 1
Rep Power: 35
vinerm will become famous soon enough
Mach number is not a good indicator of shock. Use static pressure plot to identify the shock. In Mach contours, even shear layers appear as shock.
__________________
Regards,
Vinerm

PM to be used if and only if you do not want something to be shared publicly. PM is considered to be of the least priority.
vinerm is offline   Reply With Quote

Reply

Tags
ansys, cd nozzle, ideal flow, oblique shock

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Boundary conditions for flow in nozzle kgevers FLUENT 0 July 26, 2015 12:46
Simulation of a Multiphase flow in a Convergent-Divergent Nozzle RR16988 FLUENT 1 June 9, 2015 06:10
compressible flow in a counterflow nozzle d.vamsidhar FLUENT 0 November 24, 2005 01:45
Inviscid Drag at subsonic, subcritical Mach # Axel Rohde Main CFD Forum 1 November 19, 2001 12:19
fluid flow fundas ram Main CFD Forum 5 June 17, 2000 21:31


All times are GMT -4. The time now is 05:08.